SNOW-1337069 connection pool doc fix

[sfc-gh-knozderko]

Description

SNOW-1337069 Fix note about special signs in connection string

Checklist

• Code compiles correctly
• Code is formatted according to Coding Conventions
• Created tests which fail without the change (if possible)
• All tests passing (dotnet test)
• Extended the README / documentation, if necessary
• Provide JIRA issue id (if possible) or GitHub issue id in PR name

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.31%. Comparing base (921b9df) to head (c7f4575).

Additional details and impacted files

@@                         Coverage Diff                          @@
##           pool/SNOW-860872-connection-pool     #958      +/-   ##
====================================================================
- Coverage                             85.56%   85.31%   -0.25%     
====================================================================
  Files                                   106      106              
  Lines                                 10742    10742              
  Branches                               1027     1027              
====================================================================
- Hits                                   9191     9165      -26     
- Misses                                 1302     1329      +27     
+ Partials                                249      248       -1     

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